Lymphokines like IL-1 are of multicellular origin, and through their multifaceted regulatory actions they affect a variety of different target cells during host response to infections. IL-1 at the site of inflammation activates lymphocytes, granulocytes, and fibroblasts. Moreover, IL-1 also may act as mediator of the acute-phase response, promote catabolism of structural protein and matrix and regulate the febrile response.
Two proteins that share human Interleukin-1 (IL-1) activity but are structurally distinct molecules have been identified. These proteins, termed IL-1alpha and IL-1beta, compete with one another for binding to IL-1 receptors and mediate similar biological activities. Both molecules are synthesized as large precursors (MW about 30,000 Da) that are processed to smaller biologically active forms (MW about 17,500 Da). However, they are encoded by two distinct complementary DNAs, show only a 26% amino acid homology, and have pI's (isoelectric pH's) of 5 and 7, respectively.
In U.S. Pat. No. 4,935,343 monoclonal antibodies which bind to IL-theta and do not bind to IL-1alpha (see also Kenney et J. Immunol. 138 (1987) 4236-4242). The antibodies bind to IL-1beta and block receptor binding to, and biological activity of, IL-1beta.
WO 2004/067568 reports human IL-1beta antagonists.